Photograph



May 7 1940- J. R. ALBURGER 2,199,902

PHOTOGRAPH Filed April 12, 1958 WMM noentor Bu Y dtml-neg Patented May 7, 1940 j UNITED STATES PATENT OFI-ica 3,199,902 Pno'roGaAPn James'R. Alburger, Merian, Pa., assigner to Radio Corporation of America, a corporation of Dela- Ware Application April 12, 1938, Serial No. 201,507 2 Claims. 4(Cl. 95-`-88) ll ,reduced silver grains, but also from a mordant deposited inthe gelatine and which may in itself be colored, or may be colorless and impregnated with a dye, or both.

In thel production of my improved photograph,

n I use a developer such as that referred to in vmy aforesaid application, which maintains a mordant material in solution and which,during the action of lthe developer, deposits the said material around and between the silver grains in proporu tion .to the amount of developingaction occur- ,One object of lmy invention is 4to pro-vide anv improved photograph.

'Another vobject of my invention is to provide ,o a photograph having improved contrast.

Another object of my invention is to provide a, photograph having greater density than heretofore possible. l 1

Another object of my invention is to provide u an improved photograph capable of being tinted. -Another object of my invention is to provide va photograph reducing the eiect of graininess.

Another object of my invention is to provide a photographic image which is capable of being converted into a dye image.

4 Another object of my invention is-to provide a photographic dye image coincident with a photographic silver image.

Other and incidental objects of my invention will be 'apparent to those skilled in the art from a reading of the following specification and an inspection of 4the accompanying drawing, in which Figure- 1 is a greatly enlarged view of a phow tograph, a photograph of a sound record being chosen for purposes of illustration, and

Figure 2 is a sectionalview taken along the line 2--2 of Fig. 1.

Y As shown in thev drawing, a base l of any of u the usual materials such as glass, Celluloid, pa-

.aluminum hydroxide.

per or the like, is provided. On this is superposed the usual emulsion layer 2, which may be of any convenient type such, for example, asis used on commercial motion picture lm, in' which case the base I would be of Celluloid or cellulose 5 acetate. 'I'he emulsion 2 is, lprior to exposure, replete with grains of silver salt, such as silver bromide, silver iodide, silver chloride, or a com'- bination of two or more of these substances.

Exposure is accomplished in the usual fashion, 1 and the iilm is then developed in a developer having in solution a mordanting agent such as As an example of one developer suitable for the purpose, the following may be used: I u I-Iydroquinone (para-dihydroxybenzene) grams 15 NaiSO-r rin 17 KAJ(SO4) 2-12H3O do... 38 NaOH- do 3oy 20 KBr a do--- Water to make -ccs-- 1000 An alternative formula is:l

Na2SO1 grams-.. 50 25 Mono-methyl carboxyl paramino hydroxy-- benzene (Glycin) grams.. NaOH dn 25 KA! (S04) 2 12H20 do 30 Water to make ccs 1000 30 'I'he invention is by no means limitedto the use of the foregoing two formulas, but my improved photograph may be' obtained by the use of any developer containing an appropriate mordanting material in solution. For example, I have found that 4a. developer .using any of the conventional benzene or naphthalenederivative developing agents, and having either aluminum alum or chrome alum maintained in solution by ,suf'cient alkali toredissolve the precipitate tend- 40- ing to be first formed on the addition of the alum, will accomplish my purpose.

Upon development of the exposed emulsion, the grains of silver salts, such as indicated at 3, are reduced to metallic silver in the usual discrete form. During such reduction, however, the bromine, iodine, or chlorine which is liberated fromthe silver salts reacts with the alkali of the developer to produce the corresponding sodium' salt at the point of development. 'I'his reaction drops the alum out of solution at the point of development, leaving aluminum hydroxide, chromium hydroxide or the like deposited around and between the developed silver grains, and since lthe amount of sodium hydroxide changing into a. salt is dependent upon the amount of silver changing from the halide to metallic silver, the amount of aluminum or chromium hydroxide deposited at that point corresponds to the amount of silver reduced. As is well known, these hy' any appropriate dye such as any of those which are used commercially in conjunction with aluminum hydroxide as a. mordant, these types .being generally referred to as acid dyes.. The chivo-- mium salts, having some color themselves, add

to the density ofthe silver limage Without` the addition of dye.

If desired, the appropriate dye may bel added j;

directly to the developer in appropriate amount,

subject only to the limitan-on that; in '-tmsc'ase a dye must b'e'chosen which does not react with the developing agent itself, and which of the aforesaid dyes can be used depends upon the specific developing agent chosen, and vice versa.

If desired, either before or after dyeing the deposited silver may be removed by an appropriate silver solvent such, for example, as the ,5

well known Farmers reducer, composed of a solution of sodium hyposulphite and potassium ferricyanide. For the purpose ofremoving the silver, such an agent as-thev usual `potassium bichromate-sulphuric acid solution should be m avoided, as the sulphurlc acid has a tendency to dissolve the mordant.

Having described my'invention, I claim: l. A photograph including a reduced silver image and a`v coincident aluminum hydroxide 15 mordant image. f

2.. A photograph comprising a base, a gelatine .emulsion on said base, a reduced silver image in said'emulsion, and a deposited aluminum hydroxide, mordant u image coincident with said 20 

